Regenerative receiver arrangement



Jan. 12, 1937. z 2,067,536

REGENERATIVE RECEIVER ARRARGEMENT Filed May 4, 1954 INVENTOR fen 5r A2072 ATTORNEY Patented Jan. 12, 1937 'UNiTED sm'rss PATENT OFFWE REGENERATIVE RECEIVER ARRANGEMENT Germany Application May 4, 1934, Serial No. 723,815 In Germany May 23, 1933 3 Claims.

An object of this invention is a regeneratively coupled receiver apparatus, and the chief purpose thereof is to insure constant and stable coupling relations throughout the entire range of setting.

a A second object of the invention is to provide a high degree of intermediate frequency amplification without the use of several amplifyingstages.

Other and further objects will be apparent to those skilled in the art as the description of the invention proceeds. According to the invention, recourse is had with the said end in view to the heterodyne system of reception in which the oscillations to be received are converted into a lower intermediate or transfer frequency by the aid of a preferably self-oscillating mixer tube. The output circuit of the mixer tube is in direct coupling relationship with the input circuit of the second rectifier or detector (without the use of additional amplifiers), with regeneration means for compensating for the attenuation of the coupling circuits tuned to the intermediate frequency.

Most suitably, the compensation of attenuation (or gain) is insured in the intermediate frequency circuits in this manner that the second detector tube is of the regenerative rectifier type. However, also the mixer tube could be employed at the same time for insuring de-attenuation of the intermediate frequency coupling circuit, and for this purpose hexode tubes would be particularly suited.

Figures 1 and 2 of the drawing, show schematic circuit arrangements illustrating the invention. Referring to Fig. 1 the antenna circuit A is inductively coupled to circuit E comprising secondary coil Iii tuned to the incoming signal frequency by a condenser ll whose terminals are connected to the cathode I2 and signal control grid 13 of the oscillator detector tube M. An outer grid It is connected to a suitable source of potential through the transformer secondary coil H which is tuned to the desired local oscillation frequency by condenser l8. The outer section of the tube including the plate and grid I4 is caused to oscillate by inductively coupling a primary coil H5 in the plate circuit l5 of the tube with secondary 11. Also inductively coupled to coil I6 is a circuit Z comprising transformer secondary coil H! which is tuned to the desired intermediate frequency by condenser 20. One side of condenser is conductively connected to cathode 22 of the rectifier or detector tube G while the other. side is connected to the control grid 23 through the grid leak condenser 2|. A

feedback connection to tuned circuit Z is provided by a tickler coil 25 which is included in the plate circuit E i of tube G and is in inductive coupling with coil I9. The audio frequency output of the receiver may be impressed on a sound reproducer 29 by means of an audio transformer T including primary 26 and secondary 28, the coil 26 being shunted by a condenser 21 which serves to by-pass the intermediate frequency currents. By means of the arrangement described a large degree of amplification of the signal energy at the intermediate frequency is secured without the use of separate intermediate frequency amplifier stages.

I have also found it possible to cause a large degree of intermediate frequency amplification by the use of a hexode oscillator-detector tube, especially if a tube of the type recently introduced in the art is employed. Such a tube and circuit arrangement is shown in Fig. 2 in which the antenna circuit is connected to the circuit E tuned to the signal frequency in the same manner as shown in Fig. 1. The second grid 30 serves as a screen grid to screen the signal grid 13 from the oscillator grid 3|, grid 30 being maintained at a 3! in the plate circuit I5 of the tube, coil 31 being shunted by a condenser 39 to form a circuit Z tuned to the intermediate frequency. A circuit Z also tuned to the intermediate frequency and comprising secondary coil 38 and condenser 40 may be connected to the input terminals of a tube d3 which may function as a second detector as in Fig. 1. Coil 38 may be inductively coupled to coil 36 as is the coil 31, thereby providing regeneration of the currents in the tuned circuits Z and Z since current of the intermediate frequency in coils 31 and 38 causes the potential of grid 32 to fluctuate at this frequency, thereby further increasing the intermediate frequency current in the plate circuit l5.

Having described the invention, it will be understood that I do not limit myself to the particular circuit arrangements shown but intend to include all such circuits or apparatus as come within the scope of the following claims.

What I claim and desire to secure by Letters Patent is:

1. In a radio receiver, the combination of a vacuum tube having a cathode, a signal control grid, an oscillator grid, a plate and a third grid located between said oscillator grid and said plate, a circuit tuned to the signal frequency connected between said cathode and signal control grid, a circuit tuned to an oscillation frequency differing from said signal frequency by a desired intermediate frequency connected to said oscillator grid, a circuit directly connected to said plate and tuned to the intermediate frequency, a source of positive potential connected to the low potential end of said last named circuit, and a circuit connected to said third grid and comprising a feedback coupling to said circuit tuned to the oscillation frequency and also a second feedback coupling to the circuit tuned to the intermediate frequency.

2. The combination defined in the preceding claim in which a screen grid is located between said signal control grid and said oscillator grid, and means for maintaining said screen grid at constant potential.

3. In a radio receiver, an electron discharge tube having a cathode, a plate and a signal control grid, a screen grid, an oscillator grid and an additional grid located between said cathode and plate in the order named, a circuit tunable to the radio signal frequency connected between said cathode and signal control grid, means for maintaining said screen grid at a steady potential, a circuit tuned to an oscillation frequency differing from said signal frequency by an intermediate frequency substantially lower than said signal frequency connected to said oscillator grid, a circuit connected to said additional grid and comprising two coils connected in series, a feedback connection between one of said coils and the circuit tuned to the oscillation frequency, a circuit connected at one end to said plate and at its other end to a source of positive potential and comprising a coil and condenser tuned to the intermediate frequency and a feedback connection between said last named coil and the other of said first named coils.

ERNST KLOTZ. 

